Electrical connector



Sept. 7, 1965 J. c. DAVIDSON ELECTRICAL CONNECTOR 2 Sheets-Sheet 1 FiledMarch 8, 1963 WWO? 497' INVENTOR. JAMES 6'. MV/DSW/V p 7, 1965 J. c.DAVIDSON 3,205,295

ELECTRICAL CONNECTOR Filed March 18, 1963 2 Sheets-Sheet 2 INVENTOR.1/44/55 6 DAV/06W its terminal point.

United States Patent Oflice 3,205,295 Patented Sept. 7, 1965 3,205,295ELECTRICAL CONNECTOR James C. Davidson, Gicndora, Calif., assignor toBurroughs Corporation, Detroit, Mich., a corporation of Michigan FiledMar. 18, 1963, Ser. No. 265,782 Claims. (Cl. 174-32) This inventionrelates to electrical connectors and more particularly to electricalconnectors for the interconnection of twisted pair transmission lines.

When a plurality of conductors are placed in close proximity, there is atendency for the signals travelling on one conductor to interfere withsignals travelling on adjacent conductors. This interference is commonlycalled cross-talk and is especially noticeable and detrimental in highfrequency circuits. One way to reduce the cross-talk is to entwine ortwist the pair of conductors which constitute a transmission line.Thereafter, the twisted pair of conductors may be placed adjacent toeach other without significant interference.

The twisted pair of transmission lines will usually terminate in aconnector to form a cable for the interconnection between circuits. Itis desirable to continue the twist or entwining of each pair ofconductors down to its connection with the connector in order to avoidthe cross-talk problem. In the past, the connectors have taken the formof a plurality of pins embedded in a layer of insulating material.Thereafter, two or more of the pins are interconnected by a conductor toform a terminal point for the ground conductors of the transmission linepairs. The signal conductors of each pair terminate at an individualpin. In such a construction, the ground conductors are all connected toa common point so that the twisting of a particular pair of conductorsmust be discontinued prior to the connection to the signal pin toprovide sutficient length in the ground conductor to reach Thus, theproblem of cross-talk is apparent.

However, another prior art connector overcame this problem of cross-talkby connecting the two conductors of each pair to adjacent pins on theconnector. Thus, the twisting or entwining of the pairs could becontinued down to the point of connection of each conductor. There is abig disadvantage in such a connector in that every other pin has aground conductor connected thereto. This results in a highly inefiicientuse of the pins that extend through the connector and of the availablearea in which the pins can be located.

Therefore, in accordance with the present invention, there is provided aconnector which substantially overcomes the problem of cross-talk andprovides a highly eflicient use of the pins or prongs of the connector.The connector includes a plurality of pins embedded in a layer ofinsulating material. In addition to the layer of insulating materialthere is provided a layer of conducting material on top of theinsulating material. The pins are perpendicular to the surface of thelayer of insulating material and extend away from the layer ofconducting material. There is provided a plurality of holes or aperturesin the layer of conducting material, with each hole being positioneddirectly above a pin in the layer of insulating material. Thereafter, atwisted pair of conductors advantageously have the twist extending downto the layer of conducting material, where the ground conductor isattached. Thereafter, the signal conductor is passed through an adjacenthole and connected to the pin located below the hole. Thus, the layer ofconducting material effectively forms a finite ground plane or groundplate in the connector and substantially eliminates any cross-talk.Rather than having a plurality of pins of the connector associated withthe ground conductors of the transmission lines, there may be as few asone pin associated with the ground conductors. This pin is electricallyconnected to the ground plate.

A particularly advantageous modification of the connector involves theextension of the pins associated with the signal conductors through theholes in the layer of conducting material so that the signal conductorsmay be more easily attached to the pins.

Thereafter, a further modification is particularly advantageous. Rigidconductors are attached to the layer of conducting material and extendabove the surface thereof adjacent to one of the pins so that the groundconductor may also be more easily connected. Thus, the entwining ortwisting of each pair may be continued down to the point of connection.

The above and other features and advantages of the present inventionwill be understood more clearly and fully upon consideration of thefollowing specification and drawing in which:

FIG. 1 is a pictorial diagram of a prior art connector;

FIG. 2 is a pictorial diagram of another prior art connector;

FIG. 3 is a pictorial diagram of the connector in accordance with theinvention;

further the understanding of the problems that existed in connectors fortwisted pair transmission lines. The prior art connector of FIG. 1 isrepresentative of one of the types previously employed to terminatetwisted pairs of conductors. This particular type resulted in excessivecross-talk in that the twisting of the pairs had to be discontinued atsome distance from the connection to permit sufiic'ient length for theground conductor of each pair to be connected.

The connector 10f FIG. 1 includes a plurality of pins, of which only afew are shown, embedded in a layer of insulating material 3. 0f the pinsembedded in the insulating material and extending therethrough, four areshown connected in common by a conductor 5. These four pins areseparately numbered for identification purposes. For example, the pinsthat are connected together and are associated with the ground conductorof each pair through ground conductor 5 are pins 4. Onthe other hand,the pins that are associated with the signal conductor are pins 2.

A typical pair of transmission lines 6 includes a signal conductor 7 anda ground conductor 8. The signal conductor 7 is connected to a pin 2 andthe ground conductor 8 is connected to the ground conductor 5, which isconnected to the pins 4. It is seen that the twisting or entwining ofthe conductors must be discontinued a substantial distance from theconnection to provide a sufiicient length of ground conductor 8 forconnection to pins '4. Therefore, cross-talk becomes a problem in thisprior art connector.

Another prior art connector, which overcomes this problem of cross-talk,permits the twisting of the conductors to continue down to theconnection and is shown in FIG. 2. The connector comprises a layer ofinsulating material 11 and a plurality of pins 12. A typical twistedpair of conductors includes a signal conductor 13 and a ground conductor14. The. two conductors of the pair are connected to adjacent pins sothat every other pin 12 which extends through the layer of insulatingmaterial 11 will have a ground conductor attached thereto. This resultsin a very inefiicient use of the pins, that extend through theinsulating material.

Now referring to FIG. 3, the improved electrical connector of thepresent invention will be described. The connector of FIG. 3 includes alaminated frame 21 which comprises a layer of insulating material 22anda layer of conducting material 23. A plurality of pins 24 are embeddedin the layer of insulating material 22. These pins 24 are positionedperpendicular to the flat surface of the laminated frame 21 and, extendaway from the layer of insulating material 22 on the side opposite thelayer of conducting material 23. An aperture or hole 25 is located inthe layer of insulating material 22 above each pin 24. Above each hole25 is a coaxial hole 26 in the terial and a hole 25 in the layerofinsulating material and makes contact with and is connected to one ofthe pins 24. This connection may be by a solder connection or any one ofthe other well-known ways of connecting electrical conductors to pins.The ground conductor 29 is connected to thelayerof conducting material23 adjacent to the hole 26 through which its associated signal conductorpassed. Every other twited pair of transmission ,lines will be similarlyconnected to the connector, i.e.,

the signal conductor will pass through the holes 26 and 25 tomakecontact with a pin and the ground conductor thereto.

To complete the connector, the layer of conducting-material ;23,iselectrically connected toone or more pins 30, so thatthe groundconductors of the transmission lines will be effectively connected tothe circuit to which the connector is attached. Thus, as few as one pinmay be associated with the ground or signal return conductors ratherthan having one-half of the pins required for ground conductors.

A preferred embodiment of the connector, in accordance with theinvention, is shown in FIG. 4. This connector is similar to theconnector of FIG. 3 and includes a laminated frame 21 which comprises alamina of insulating material 22 and a lamina of conducting material 23.The pins 24, which are embedded in the laminaof insulating material,extend through holes 26 in the layer of conducting material 23.Thereafter, the signal conductor of ;the transmission lines may be moreeasily connected to .the pins above the finite groundplane or groundplate -formed by the layerof conducting material 23. Additionally, rigidconductors 31 are embedded in or con- .nected to the layer of conductingmaterial 23 and extend above it so that the ground conductors of thetransmission lines may also be more easily connected. The layer ofconducting material 23 iselectrically connected to at least one pin 30to carry all of the ground conductors or signal return conductors of thepaired conductors into the next circuit.

A modification to the connector shownin FIG 4 is shown in FIG. 5. To theconnector of FIG. 4 there is added a layer of insulating material 33 ontop of the layer of conducting material 23. This is provided to moreeffectively isolate the pins 24 and the rigid conductors 31.Additionally, the layer of insulating material 33 will make theconnector more rigid and durable.

After all of the conductors are connected to the connectors of FIGS. 3,4 and S, the unit may be advantageously encased in a solid material, e.g., a plastic, to protect the electrical connections and the wires.

What is claimed is:

1. An electrical connector comprising a first layer of insulatingmaterial, a second layer of insulating material, a layer of conductingmaterial sandwiched between the first and second layers of insulatingmaterial, a plurality of apertures located in the layer of conductingmaterial and positioned in a spaced-apart relationship, a plurality ofpins, each one of the pins extending through one of the apertures andembedded in the first layer of insulating material and the second layerof insulating material, the pins extending beyond the second layer ofinsulating material to form the prongs of the connector and extending inthe opposite direction above the first layer of insulating material toform terminals for electrical conductors, rigid conductors embedded inthe layer of conducting material and extending through the first layerof insulating material to form terminals for electrical conductors, andat least one pin embedded in the layer of conducting material andextending through the second layer of insulating material to form one ofthe prongs of the connector.

2. In combination, a layer of insulating material, a plurality of pinsembedded in the layer of insulating material, a layer of conductingmaterial positioned on top of the layer of insulating material, at leastone of the pins being in electrical contact with the layer of conductingmaterial, a plurality of paired transmission lines, each pair includinga signal conductor and a signal return conductor, the signal conductorand the signal return conductor of each pair being intertwined, meansfor connecting each signal conductor to one of the pins, and means forphysically connecting each signal return conductor to the layer ofconducting material adjacent the pin of its associated signal conductor.

3. An electrical connector for twisted pair transmission linescomprising a layer of insulating material, a plurality of pins embeddedin the insulating layer, a ground plate .through an aperture andconnected to the pin therebelow,

the signal return conductor of each pair being connected to the groundplate adjacent to the aperture associated with the signal conductor ofthe pair, and at least one pin passing through the layer of insulatingmaterial and making electrical contact with the ground plate.

4. In combination, a layer of insulating material, a layer of conductingmaterial attached to the layer of insulating material, a plurality ofpins embedded in the layer of insulating material and positionedperpendicular to the plane of the layers, the pins extending away fromthe layer of insulating material to form the prongs of the connector andextending in the opposite direction above the layer of conductingmaterial to form electrical terminals, a plurality of rigid conductorsattached to the layer of conducting material and extending in adirection parallel to the plurality of pins above the layer ofconducting material, a twisted pair of conductors connected to adjacentpins and rigid conductors so that the signal conductor will be coupledthrough the layers by the pins and the ground conductor will be coupledto the layer of conducting material by the rigid conductors, and atleast one pin extending through the layer of insulating material fromthe layer .of conducting material and in contact with the layer ofconducting material.

5. In combination, a laminated frame including a layer .of insulatingmaterial and a layer of conducting material,

a plurality of conductive pins embedded in the layer of insulatingmaterial, the pins positioned perpendicular to the laminated frame andextending away from the layer of insulating material on the sideopposite the layer of conducting material, apertures in the conductingmaterial above each pin, and a plurality of twisted pairs of conductors,the twist extending down to the layer of conducting material, one of theconductors of each pair extending through an aperture and connected to apin, and the other conductor of each pair connected to the layer ofconducting material adjacent to the aperture of its associated signalconductor, at least one pin being in electrical contact with the layerof conducting material.

References Cited by the Examiner UNITED STATES PATENTS Worthington.

Bowers 33918 Gauthier 339-14 XR Fett et al 17432 XR Jacobs 339-198 XRTrent.

10 DARRELL L. CLAY, Primary Examiner.

JOHN P. WILDMAN, JOHN F. BURNS, Examiners.

4. IN COMBINATION, A LAYER OF INSULATING MATERIAL, A LAYER OF CONDUCTINGMATERIAL ATTACHED TO THE LAYER OF INSULATING MATERIAL, A PLURALITY OFPINS EMBEDDED IN THE LAYER OF INSULATING MATERIAL AND POSITIONEDPERPENDICULAR TO THE PLANE OF THE LAYERS, THE PINS EXTENDING AWAY FROMTHE LAYER OF INSULATING MATERIAL TO FORM THE PRONGS OF THE CONNECTOR ANDEXTENDING IN THE OPPOSITE DIRECTION ABOVE THE LAYER OF CONDUCTINGMATERIAL TO FORM ELECTRICAL TERMINALS, A PLURALITY OF RIGID CONDUCTORSATTACHED TO THE LAYER OF CONDUCTING MATERIAL AND EXTENDING IN ADIRECTION PARALLEL TO THE PLURALITY OF PINS ABOVE THE LAYER OFCONDUCTING MATERIAL, A TWISTED PAIR OF CONDUCTGORS CONNECTED TO ADJACENTPINS AND RIGID CONDUCTORS SO THAT THE SIGNAL CONDUCTOR WILL